Various process systems (e.g., reactor systems) involve use of relatively high temperature and/or relatively low temperature process streams. The cooling and/or heating of such streams may involve significant energy costs. To reduce such costs the process streams may be thermally contacted to exchange heat and reduce the energy costs. However, such thermal contact may be difficult or even prohibited when such process gases contain an amount of corrosive gases. The presence of corrosive gases has often conventionally required the process gas be quickly heated or cooled to a temperature at which the gases are less corrosive before heat exchange with other process gases may occur which increases the energy requirements of the system.
An example of such a system in which corrosive gases are produced thereby limiting heat exchange with other process gases is a reaction system in which silicon tetrachloride is reacted with hydrogen to produce trichlorosilane. This reaction produces hydrogen chloride as a by-product. As the equilibrium reaction toward trichlorosilane is favorable at high temperatures, the hydrogen chloride is typically at a high temperature which conventionally has required it to be quickly quenched. This conventionally has limited the amount of heat that can be transferred from the product gas to other process streams.
Accordingly a continuing need exists for reactor and heat exchange systems that allow process gases (e.g., gases containing a corrosive gas) to be heated or cooled relatively soon after production of the product gas. A continuing need also exists for heat exchangers that improve the temperature and flow profiles of the incoming process streams. A continuing need also exits for methods that involve use of such heat exchangers and/or reactor vessels.